The proposed research program will investigate the relation between the cytochrome p4501A1 (CYP1A1)-dependent monoxygenase system, which is involved in the metabolism of aromatic hydrocarbons contained in cigarette smoke, and chronic obstructive pulmonary disease (COPD). Experiments relevant to the first specific aim will quantitatively assess the activity of the CYP1A1 gene and enzyme in individuals with the without COPD. Experiments relevant to the second and third specific aims will determine the distribution of CYP1A1 genotypes in African-American individuals with and without chronic obstructive lung disease, and the functional significance (and potential relation to different disease susceptibility), of the African-American specific CYP1A1 polymorphism (CYP1A1-AA). These experiments are designed to examine the importance of the P450-dependent oxidative system in respiratory cell function and disease, and increase the information that is expected to be derived from ongoing studies related to lung cancer.